Cutting device with detachable cutter head for cutting sheet material length-wise

ABSTRACT

The device for cutting sheet material length-wise includes a knife holder assembly which can be linked to a cutter bar. The knife holder assembly has a support body and a cutter head which carried a circular cutting knife and which can be adjusted vertically in relation to the support body. The knife holder assembly also has a connecting plug assembly for connecting the support body to the cutter head. The direction of connection extends in the plane of the circular cutting knife.

Several knife holders attached to a cutter bar are used for cuttingsheet material lengthwise. The individual knife holders essentiallycomprise one controllable lowering device, on which a circular cuttingknife is positioned on a cutter head, such that it can rotate. Theindividual knife holders are mounted detachably on the cutter bar, sothat the desired cutting widths can be adjusted by adjusting the mutualdistances between neighboring knife holders. The circular cutting kniveswear out over time and must therefore be replaced from time to time tomaintain the cutting quality. The circular cutting knife, which isattached with the aid of a ring nut to the cutter head, can be pulledoff the cutter head once the ring nut is unscrewed and can be replacedwith a new circular cutting knife. However, these operations are timeconsuming and, in particular, are difficult to carry out when cuttingnarrow material sheets. With extremely narrow cutting widths, therequired access to the ring nut does not even exist, so that the knifeholder must be removed altogether.

It is the object of the invention to create a device for cuttingmaterial sheets of the aforementioned type in lengthwise direction,which device permits an easy replacement of damaged or worn circularcutting knives.

This object is solved according to the invention with a device forcutting material sheets lengthwise, which device contains a knife holderthat can be attached to a cutter bar. The knife holder essentiallyconsists of a support body and a cutter head that is provided with acircular cutting knife. The cutter head is adjustable in vertical andhorizontal direction, relative to the support body, and is provided withan interlocking, plug-type connector for connecting the support body tothe cutter head and/or the cutter bar. The plug-in direction of thisconnector extends in the plane for the circular cutting knife.

With a knife holder designed in this way, it is possible to replace adamaged or worn circular cutting knife without having to remove theknife holder from the cutter bar, even if the individual knife holdersare arranged tightly adjoining on the cutter bar. The specified positionof the knife holder, relative to the adjacent knife holders, is thusmaintained. Following the release of the interlocking, the cutter headas a whole can be pulled off the support body toward the front. In placeof the cutter head with the damaged circular cutting knife, a cutterhead with a new circular cutting knife is then fitted onto the supportbody and is interlocked with this body, so that the full function isrestored once more.

The solution according to the invention can also be used with a devicefor cutting material sheets lengthwise, for which the knife holders arenot connected directly to the cutter bar, but to an adapter slide thatcan be moved along the cutter bar and can be locked in place thereon.With a device of this type, a corresponding plug-type connector betweensupport body and adapter slide can be provided in addition to or inplace of the plug-type connector between cutter head and support body.Given a system of this type and following the release of the interlockedplug-in connection, the complete knife holder is lifted in upwarddirection off the adapter slide and is replaced by a new knife holder.This occurs without a change in the positioning, relative to theneighboring knife holders, which is predetermined by the positioning ofthe adapter slide. A measure of this type is required, in particular, ifthe standard pneumatic adjustment device in the support body for thevertical movement of the cutter head no longer operates without problemsor is not operational at all, for example as a result of leaks in thepiston-cylinder system.

One preferred embodiment of the invention provides that the plug-typeconnector is formed by a guide pin on the one part and a correspondingreceptacle for the guide pin on the other part, as well as thecoordinated form-fitting surfaces on both parts. The preferablycylindrical guide pin can be bought cheaply as prefabricated,semi-finished product. Accordingly, the hole for the guide pin is simplya corresponding mating bore. As a result of this arrangement of thecoordinated form-fitting surfaces, which function to tension the twoparts against each other via the interlocking, it is ensured that thetwo parts are rigidly connected and that the breakdown torque as well asthe torque, introduced by the cutting forces, are reliably absorbed.

One advantageous embodiment of the invention furthermore provides thatthe interlocking connection is formed by a screw tensioning the guidepin against the hole. An interlocking connection of this type is easy toproduce since the guide pin is provided with an axial thread bore. Inaddition, it has the advantage that the interlocking is also accessiblein plug-in direction. In that case, the screw can be designed, forexample, as hexagon socket screw, so that it is easy to create theinterlocking connection by using an appropriate screwdriver.

According to one preferred embodiment of the invention, the coordinatedformlocking surfaces are formed by a cross bolt on the guide pin and arecess in the receiving mating bore.

Another embodiment of the invention provides that the form-lockingsurfaces are formed by coordinated wedge-shaped surfaces that face eachother. This embodiment has the advantage of providing relatively large,contacting surface areas, so that the permissible surface pressures arenot exceeded, even for high pressing forces. Another advantage of thisembodiment having wedge-shaped surfaces is that there is no play inplug-type connector because the surfaces are tensioned against eachother. The embodiment can also be used in conjunction with thepreviously described cross bolts.

The invention is explained in further detail in the following with theaid of schematic drawings of exemplary embodiments, which show in:

FIG. 1 A frontal view of a cutter bar with several knife holders.

FIG. 2 A view from the side of a support body for a knife holder.

FIG. 3 A modified embodiment of the plug-type connector.

The frontal view according to FIG. 1 shows a cutter bar 1 of a devicefor cutting material sheets in lengthwise direction. Four knife holders2.1, 2.2, 2.3 and 2.4 are attached to this cutter bar. The knife holders2 comprise respectively one support body 3, on which a cutter head 4with freely rotating circular cutting knife 5 is mounted, such that itcan be lifted and lowered in vertical direction, which support body canalso be pulled out horizontally. In the illustration shown herein, ahand protector furthermore covers the cutter head 4, so that only thelower cutting region of the circular cutting knife 5 is visible.Following the horizontal adjustment, the circular cutting knife 5operates against cutting rings 6, which are mounted on a knife shaft 7at a distance to each other.

The individual knife holders 2 can be displaced relative to each otheralong the cutter bar 1 in horizontal direction and can be securedrelative to each other at predetermined distances. For this, fourparallel guide bars 8.1, 8.2, 8.3 and 8.4 are provided at a distance toeach other on the cutter bar 1. On these guide bars, the support bodies3 of knife holders 2 are respectively positioned via an adapter slide 10(FIG. 2), such that they can be moved and locked in place. Each adapterslide 10 is provided with a guide carriage 9.1 and 9.2, such that theadapter slides 10 of neighboring knife holders are guided alternately onan upper pair of guide bars 8.1 and 8.3 and, respectively, on a lowerpair of guide bars 8.2 and 8.4. Thus, for example, the adapter slide 10of the knife holder 2.1 glides on the guide bars 8.1 and 8.3, whereasthe adapter slide 10 of the neighboring knife holder 2.2 glides on theguide bars 8.2 and 8.4. As a result, the lever arm formed respectivelyby the guide bars 8.1, 8.2, 8.3 and 8.4 with the coordinated parts ofadapter slide 10, which serves to absorb the cutting forces (arrow S)effective in crosswise direction to the cutting plane of circularcutting knife 5, is enlarged correspondingly. The complete arrangementis thus more rigid, so that any defects in the cutting quality areavoided.

As shown for the knife holders 2.3 and 2.4, this arrangement offers theoption of positioning the knife holders directly adjacent to each othersince the guide slides 9.1 and 9.2 for structural reasons have a widerwidth than the maximum width of the support bodies 3 for knife holders2. This is the case because the adapter slides 10, with their respectiveends of guide slides 9 that project over the width of the support bodies3, can “move underneath” the support body 3 of the neighboring knifeholder 2.

With this embodiment, the knife holders 2 that are guided along and heldin place on the cutter bar with the aid of adapter slides 10 can besecured with the usual narrow spacing on the cutter bar 1 since theadapter slides 10 are advantageously held in place on the cutter bar 1with ball bearing guides, which accordingly are embodied to be widerthan the support bodies 3 of knife holders 2.

The view from the side according to FIG. 2 shows essentially only thesupport body 3 of a knife holder 2 with the herein relevant connectionsto the cutter head 4 on the one side and an adapter slide 10 on theother side.

The support body 3 is provided with an adjustment element 11, which isguided perpendicular inside the support body 3, as well as with apneumatic adjustment drive of a known design for the downward movement,which is not shown further herein. The adjustment drive furthermore hasa resetting spring for the upward movement after the pressure is removedfrom the adjustment drive.

The cutter head 4 is connected via a plug-type connector 12 to theadjustment element 11. The plug-type connector 12 for the exemplaryembodiment shown herein comprises a guide pin 13 with cylindricalcross-section, which is inserted into a mating bore 11.1 on theadjustment element 11 and is secured with a bolt 14 on the adjustmentelement 11. The direction of insertion of the guide pin 13 (plug-indirection) lies in the cutting knife plane a shown in FIG. 1 for one ofthe cutting knives 5.

The cutter head 4 has an extension, which serves a receptacle 15 for thefree end of guide pin 13 and is provided with a mating bore 16. The freelength of guide pin 13 is somewhat shorter than the length of the matingbore 16 and is provided with an axial tapped hole 17. For theinterlocking, a hexagon socket screw 18 can be screwed into this tappedhole 17, through which the cutter head 4 with its receptacle 15 can betensioned against the guide pin 13 in axial direction.

In order to achieve an exact positioning and simultaneously create anon-rotating plug-type connection, a cross bolt 19 is arranged on theguide pin 13, in the area of the surfaces of adjustment element 11 andreceptacle 15, which face each other. A corresponding semi-cylindricalrecess 19.1 on the receptacle 15 is assigned to this cross bolt. If thescrew 18, which serves as interlocking device, is used to tension thecutter head 4, then the semi-cylindrical recess 19.1 on the receptacle15 is pressed against the cylindrical outside surface of cross bolt 19,wherein the contacting surfaces of semicylindrical cylindrical recess19.1 and cross bolt 19 form coordinated form-fitting surfaces. Theform-fitting connection between cutter head 4 and adjustment element 11of support body 3, which is established in this way via the plug-typeconnector 12, is sufficient to reliably absorb the cutting forcesgenerated during the operation (arrow S in FIG. 1).

The screw 18 that functions as interlocking device is unscrewed in orderto replace a cutter head 4. Even if the individual knife holders 2 arepositioned tightly sideby-side, as shown in FIG. 1, a cutter head 4 canbe pulled toward the front in the direction of arrow 21. In order toprovide easier access for this operation, an undercut recess 23 isprovided on the forward pointing frontal surface 22 of cutter head 4,into which a hook-shaped removal tool can be inserted.

A knife holder 2, designed in this way, can be connected detachably tothe cutter bar 1, in the standard way via a prism-shaped clamping railon the cutter bar 1 on one side and a corresponding clamping part on thesupport body 3.

With the exemplary embodiment shown herein, for which the support body 3can be connected via an adapter slide 10 to the cutter bar 1, acorrespondingly configured plug-type connector 24 is also provided forthe connection between support body 3 and adapter slide 10. Thisplug-type connector is configured in the same way as the previouslydescribed plug-type connector between adjustment element 11 and cutterhead 4. With the adapter slide 10, a guide pin 13.1 is₁ via a cross pin14.1, a partial length of which projects freely upward from the adapterslide 10.

₁ Note: This sentence is complete.

The support body 3 is provided with a corresponding receptacle 15.1,which in turn contains a mating bore 16.1, so that the support body 3can be fitted onto the free end of guide pin 13.1.

A screw 18.1 that is screwed into an inside thread 17.1 in turn servesas interlocking device. The form-fitting surfaces are again provided bya cylindrical cross bolt 19.2, with which the receptacle 15.1 makescontact in a form-fitting manner with a cylindrical surface 19.3.

With this type of interlocking connection, the screw 18.1 is alsoinitially unscrewed to remove the complete knife holder 2. Followingthis, the complete knife holder 2 can then be pulled off in upwarddirection.

FIG. 3 shows another exemplary embodiment for mounting the guide pin,for example on the adjustment element 11. With this type of design, aguide pin 13 is used, which is provided on both ends with an axialinside thread 17 and 26. The guide pin is furthermore provided in thecenter region with a cross bolt 19. The guide pin 13 is inserted into acorresponding mating bore 25 on the adjustment element 11 and, with theaid of a fastening screw 27, is tensioned tightly with the adjustmentelement 11 against the cross bolt 19. In this case as well,corresponding semi-cylindrical contact surfaces are provided on theadjustment element 11. The cutter head 4 (only indicated herein) is thenfitted onto the free end of guide pin 13— as described with the aid ofFIG. 2—and is tensioned in the previously described manner. With thistype of design, it is also possible to remove the cutter head 4 if thefastening screw 27 is unscrewed in place of the screw 18. Thus, accessis provided from both sides.

With the exemplary embodiments described herein with the aid of FIG. 2and FIG. 3, the form-fitting surface between the two parts that areconnected with the plug-type connector can be formed by the surfaces ofthe two parts that face each other instead of the cross bolt 19. For theembodiment according to FIG. 3, for example, a recess with largerdimensions can be provided in the area of the cross bolt in place of theonly schematically indicated recess 15 in cutter head 4 and the facingsurfaces 28 and 29 can be configured as wedge-shaped surfaces. Thus, ifthe two parts are tensioned against each other with the screw 18, thesurfaces 28 and 29 are not only pressed against each other, but are alsodisplaced against each other within the range of a possible play, so asto eliminate the play between the free end of the guide pin and theassociated mating bore in the receptacle 15.

What is claimed is:
 1. A device for cutting material sheets lengthwise,comprising (a) a knife holder including (1) a support body; (2) anadjustment element movably guided in said support body and having afirst bore; and (3) a cutter head having a second bore being in anend-to-end alignment with said first bore; said cutter head being acomponent separate from said adjustment element; (b) means for mountingsaid support body on a cutter bar; (c) a circular cutting kniferotatably mounted on said cutter head and defining a cutting knifeplane; and (d) a connecting plug assembly including (1) a guide pinpositioned in the end-to-end aligned first and second bores forconnecting said adjustment element with said cutter head; said first andsecond bores defining a plug-in direction for said guide pin; saidplug-in direction lying in said cutting knife plane; and (2) a lockingcomponent having a tightened state and a released state; in saidtightened state the locking component engaging said guide pin andclamping said adjustment element and said cutter head to one anotherthrough said guide pin; in said released state of said locking componentsaid cutter head being removable from said adjustment element; (3) afirst surface forming part of said adjustment element; and (4) a secondsurface forming part of said cutter head; said first and second surfacesfacing one another; in said tightened state said locking componentclamping said first and second surfaces to one another.
 2. The device asdefined in claim 1, wherein said second surface has a shape conformingto said first surface; said first and second surfaces being orientedobliquely to said plug-in direction; in said tightened state saidlocking component clamping said first and second surfaces to one anotherin said plug-in direction.
 3. A device for cutting material sheetslengthwise, comprising (a) a knife holder including (1) a support body;(2) an adjustment element movably guided in said support body and havinga first bore; and (3) a cutter head having a second bore being in anend-to-end alignment with said first bore; said cutter head being acomponent separate from said adjustment element; (b) means for mountingsaid support body on a cutter bar; (c) a circular cutting kniferotatably mounted on said cutter head and defining a cutting knifeplane; and (d) a connecting plug assembly including (1) a guide pinpositioned in the end-to-end aligned first and second bores forconnecting said adjustment element with said cutter head; said first andsecond bores defining a plug-in direction for said guide pin; saidplug-in direction lying in said cutting knife plane; (2) a cross bolt onsaid guide pin; (3) a locking component having a tightened state and areleased state; in said tightened state the locking component engagingsaid guide pin and clamping said adjustment element and said cutter headto one another through said guide pin; in said released state of saidlocking component said cutter head being removable from said adjustmentelement; (4) a first surface forming part of a circumferential surfaceportion of said cross bolt; and (5) a second surface forming part ofsaid cutter head and having a shape conforming to said first surface;said first and second surfaces facing one another; in said tightenedstat said locking component clamping said first and second surfaces toone another.